A model was proposed as an alternative to current models for categorical perception, which refers to the apparent responding to stimuli only in absolute terms. The model proposed that a single (common) factor causes both a peak in the discrimination function and a categorical dichotomy and thus the correlation between the two. (Editor/RK)

This paper describes NEOMYCIN, a computer program that models one physician's diagnostic reasoning within a limited area of medicine. NEOMYCIN's knowledge base and reasoning procedure constitute a model of how human knowledge is organized and how it is used in diagnosis. The hypothesis is tested that such a procedure can be used to simulate both…